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<head><meta charset="utf-8"><title>weekly meeting 2019-01-28 · wg-traits · Zulip Chat Archive</title></head>
<h2>Stream: <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/index.html">wg-traits</a></h2>
<h3>Topic: <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/weekly.20meeting.202019-01-28.html">weekly meeting 2019-01-28</a></h3>

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<a name="157048932"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/weekly%20meeting%202019-01-28/near/157048932" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/weekly.20meeting.202019-01-28.html#157048932">(Jan 28 2019 at 19:04)</a>:</h4>
<p>Hi <span class="user-group-mention" data-user-group-id="692">@WG-compiler-traits</span>, how goes? <span aria-label="wave" class="emoji emoji-1f44b" role="img" title="wave">:wave:</span> </p>
<p>I'm just coming off another call. Be back in a sec.</p>



<a name="157049355"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/weekly%20meeting%202019-01-28/near/157049355" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/weekly.20meeting.202019-01-28.html#157049355">(Jan 28 2019 at 19:10)</a>:</h4>
<p>(back)</p>



<a name="157049536"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/weekly%20meeting%202019-01-28/near/157049536" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/weekly.20meeting.202019-01-28.html#157049536">(Jan 28 2019 at 19:11)</a>:</h4>
<p>one thing I was thinking about</p>



<a name="157049615"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/weekly%20meeting%202019-01-28/near/157049615" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/weekly.20meeting.202019-01-28.html#157049615">(Jan 28 2019 at 19:11)</a>:</h4>
<p>I'm not exactly sure how many folks are coming to All Hands, but I think a number of us from this group</p>



<a name="157049644"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/weekly%20meeting%202019-01-28/near/157049644" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/weekly.20meeting.202019-01-28.html#157049644">(Jan 28 2019 at 19:11)</a>:</h4>
<p>I'm not 100% sure yet of what the meeting strutures will be, but I'm contemplating the idea of having at least one (maybe two) breakout sessions where people can do some focused design on something and then talk about it</p>



<a name="157049652"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/weekly%20meeting%202019-01-28/near/157049652" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/weekly.20meeting.202019-01-28.html#157049652">(Jan 28 2019 at 19:12)</a>:</h4>
<p>and I thought it might be interesting to brainstorm what some trait-related things might be</p>



<a name="157049700"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/weekly%20meeting%202019-01-28/near/157049700" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/weekly.20meeting.202019-01-28.html#157049700">(Jan 28 2019 at 19:12)</a>:</h4>
<p>one thing that jumped to mind was <code>dyn Trait</code> upcast</p>



<a name="157049714"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/weekly%20meeting%202019-01-28/near/157049714" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/weekly.20meeting.202019-01-28.html#157049714">(Jan 28 2019 at 19:12)</a>:</h4>
<p>basically walking through what it would take to make that really work at runtime etc</p>



<a name="157049765"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/weekly%20meeting%202019-01-28/near/157049765" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/weekly.20meeting.202019-01-28.html#157049765">(Jan 28 2019 at 19:13)</a>:</h4>
<p>I do think it's a good idea also to use some time to talk about chalk, but I'm not 100% sure in what form.  I think I was planning on having at least one meeting to kind of go over the lowering rules, probably talk some about implied bounds, maybe dive into some of the more advanced stuff -- but this would be a longer, focused meeting.</p>



<a name="157049779"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/weekly%20meeting%202019-01-28/near/157049779" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> centril <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/weekly.20meeting.202019-01-28.html#157049779">(Jan 28 2019 at 19:13)</a>:</h4>
<p>re. runtime aspects of upcasting; does that tie into multi trait objects?</p>



<a name="157049787"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/weekly%20meeting%202019-01-28/near/157049787" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/weekly.20meeting.202019-01-28.html#157049787">(Jan 28 2019 at 19:13)</a>:</h4>
<p>I definitely think when it comes to chalk it's worth separating out the sort of "high-level" stuff from the "integrating into rustc" details</p>



<a name="157049838"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/weekly%20meeting%202019-01-28/near/157049838" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/weekly.20meeting.202019-01-28.html#157049838">(Jan 28 2019 at 19:14)</a>:</h4>
<blockquote>
<p>re. runtime aspects of upcasting; does that tie into multi trait objects?</p>
</blockquote>
<p>I'd prefer to try and separate them</p>



<a name="157049844"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/weekly%20meeting%202019-01-28/near/157049844" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/weekly.20meeting.202019-01-28.html#157049844">(Jan 28 2019 at 19:14)</a>:</h4>
<p>but that is another thing that might be good for the list</p>



<a name="157049853"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/weekly%20meeting%202019-01-28/near/157049853" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/weekly.20meeting.202019-01-28.html#157049853">(Jan 28 2019 at 19:14)</a>:</h4>
<p>(and/or maybe they are inseparable? but I think probably not)</p>



<a name="157049896"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/weekly%20meeting%202019-01-28/near/157049896" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/weekly.20meeting.202019-01-28.html#157049896">(Jan 28 2019 at 19:15)</a>:</h4>
<p>I think my goal here would be for folks to talk it out, sketch a design, with the goal of identifying not only how to do things, but which things are more complex than you might think and require broader discussion (maybe even lang team discusison)</p>



<a name="157050058"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/weekly%20meeting%202019-01-28/near/157050058" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/weekly.20meeting.202019-01-28.html#157050058">(Jan 28 2019 at 19:17)</a>:</h4>
<p>I have a <a href="https://docs.google.com/spreadsheets/d/1kRABnwAIVF_w-n67Wf_vaR6avzKWRkpbTXotLq_GCXE/edit#gid=0" target="_blank" title="https://docs.google.com/spreadsheets/d/1kRABnwAIVF_w-n67Wf_vaR6avzKWRkpbTXotLq_GCXE/edit#gid=0">google spreadsheet</a> you can click on to see my current thinking, though I have to circle back with aturon to get an idea of current timing etc</p>



<a name="157050174"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/weekly%20meeting%202019-01-28/near/157050174" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> centril <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/weekly.20meeting.202019-01-28.html#157050174">(Jan 28 2019 at 19:18)</a>:</h4>
<p>(It does feel like they are linked at least; e.g. <code>dyn A + B -&gt; dyn A</code> is a sort of upcast; but depending on how multi trait objects are represented that could be easy or hard?)</p>



<a name="157050242"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/weekly%20meeting%202019-01-28/near/157050242" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/weekly.20meeting.202019-01-28.html#157050242">(Jan 28 2019 at 19:19)</a>:</h4>
<p><span class="user-mention" data-user-id="131694">@scalexm</span>, in terms of chalk implementation, I was thinking that one topic that may be worth "breaking out" is discussing the algorithm for "given a goal to prove, what are the potentially relevant program clauses" -- i.e., what queries do we want for that, etc</p>



<a name="157050281"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/weekly%20meeting%202019-01-28/near/157050281" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> scalexm <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/weekly.20meeting.202019-01-28.html#157050281">(Jan 28 2019 at 19:19)</a>:</h4>
<p><span class="user-mention" data-user-id="116009">@nikomatsakis</span> Mmh ok</p>



<a name="157050343"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/weekly%20meeting%202019-01-28/near/157050343" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> scalexm <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/weekly.20meeting.202019-01-28.html#157050343">(Jan 28 2019 at 19:20)</a>:</h4>
<p>The algorithm as it exists right now is not overly complicated</p>



<a name="157050350"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/weekly%20meeting%202019-01-28/near/157050350" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> scalexm <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/weekly.20meeting.202019-01-28.html#157050350">(Jan 28 2019 at 19:20)</a>:</h4>
<p>But we may discuss how to enhance it for sure</p>



<a name="157050371"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/weekly%20meeting%202019-01-28/near/157050371" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/weekly.20meeting.202019-01-28.html#157050371">(Jan 28 2019 at 19:20)</a>:</h4>
<blockquote>
<p>(It does feel like they are linked at least; e.g. <code>dyn A + B -&gt; dyn A</code> is a sort of upcast; but depending on how multi trait objects are represented that could be easy or hard?)</p>
</blockquote>
<p>yes, they are certainly <em>linked</em> but I think that link may be largely one-way. I had always <em>imagined</em> that <code>dyn (A+B)</code> would have two distinct vtables, but you could of course model it with one "meta vtable". Either way though, I <em>think</em> this is sort of building on the case of <code>dyn A</code> to <code>dyn B</code> (where <code>A: B</code>)</p>



<a name="157050382"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/weekly%20meeting%202019-01-28/near/157050382" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/weekly.20meeting.202019-01-28.html#157050382">(Jan 28 2019 at 19:20)</a>:</h4>
<blockquote>
<p>But we may discuss how to enhance it for sure</p>
</blockquote>
<p>this is what I imagined, but maybe it's not worthwhile?</p>



<a name="157050419"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/weekly%20meeting%202019-01-28/near/157050419" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> scalexm <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/weekly.20meeting.202019-01-28.html#157050419">(Jan 28 2019 at 19:21)</a>:</h4>
<p>I don’t know</p>



<a name="157050426"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/weekly%20meeting%202019-01-28/near/157050426" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/weekly.20meeting.202019-01-28.html#157050426">(Jan 28 2019 at 19:21)</a>:</h4>
<p>another implementation detail I think is interesting is how to handle the infernce context, but I think that will be more relevant to discuss in context of IDE</p>



<a name="157050441"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/weekly%20meeting%202019-01-28/near/157050441" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/weekly.20meeting.202019-01-28.html#157050441">(Jan 28 2019 at 19:21)</a>:</h4>
<p>i.e., that's not something to discuss likely entirely in isolation</p>



<a name="157050518"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/weekly%20meeting%202019-01-28/near/157050518" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/weekly.20meeting.202019-01-28.html#157050518">(Jan 28 2019 at 19:22)</a>:</h4>
<p>I also think we can to some extent create new breakout topics on the fly :) I'm mostly brainstorming</p>



<a name="157050522"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/weekly%20meeting%202019-01-28/near/157050522" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> scalexm <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/weekly.20meeting.202019-01-28.html#157050522">(Jan 28 2019 at 19:22)</a>:</h4>
<p>Maybe we should try to discuss the chalk integration as a whole, as I think not a lot of people have a clear view of how the process is going, and it may help new people at the All Hands to start being interested in working on it</p>



<a name="157050532"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/weekly%20meeting%202019-01-28/near/157050532" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/weekly.20meeting.202019-01-28.html#157050532">(Jan 28 2019 at 19:22)</a>:</h4>
<p>e.g., maybe if we talk out the chalk lowering rules, a good topic will emerge from that</p>



<a name="157050555"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/weekly%20meeting%202019-01-28/near/157050555" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/weekly.20meeting.202019-01-28.html#157050555">(Jan 28 2019 at 19:22)</a>:</h4>
<blockquote>
<p>Maybe we should try to discuss the chalk integration as a whole, as I think not a lot of people have a clear view of how the process is going, and it may help new people at the All Hands to start being interested in working on it</p>
</blockquote>
<p>which side of it are you thinking here</p>



<a name="157050557"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/weekly%20meeting%202019-01-28/near/157050557" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/weekly.20meeting.202019-01-28.html#157050557">(Jan 28 2019 at 19:22)</a>:</h4>
<p>like how it works from impl side?</p>



<a name="157050662"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/weekly%20meeting%202019-01-28/near/157050662" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> scalexm <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/weekly.20meeting.202019-01-28.html#157050662">(Jan 28 2019 at 19:24)</a>:</h4>
<blockquote>
<p>like how it works from impl side?</p>
</blockquote>
<p>Yes, I think so?</p>



<a name="157050681"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/weekly%20meeting%202019-01-28/near/157050681" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/weekly.20meeting.202019-01-28.html#157050681">(Jan 28 2019 at 19:24)</a>:</h4>
<p>yes, ok</p>



<a name="157050689"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/weekly%20meeting%202019-01-28/near/157050689" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/weekly.20meeting.202019-01-28.html#157050689">(Jan 28 2019 at 19:24)</a>:</h4>
<p>I was thinking of it for sure</p>



<a name="157050702"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/weekly%20meeting%202019-01-28/near/157050702" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/weekly.20meeting.202019-01-28.html#157050702">(Jan 28 2019 at 19:24)</a>:</h4>
<p>not sure if there will be a slot for that</p>



<a name="157050715"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/weekly%20meeting%202019-01-28/near/157050715" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/weekly.20meeting.202019-01-28.html#157050715">(Jan 28 2019 at 19:25)</a>:</h4>
<p>(although it could take the place of a breakout)</p>



<a name="157050736"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/weekly%20meeting%202019-01-28/near/157050736" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/weekly.20meeting.202019-01-28.html#157050736">(Jan 28 2019 at 19:25)</a>:</h4>
<p>it does feel like it would be a good thing to talk over though</p>



<a name="157050771"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/weekly%20meeting%202019-01-28/near/157050771" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/weekly.20meeting.202019-01-28.html#157050771">(Jan 28 2019 at 19:26)</a>:</h4>
<p>(I'm wondering a bit if there is broader concept worth digging into; e.g., maybe talking about the future of the type checker -- or maybe that's too premature)</p>



<a name="157050821"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/weekly%20meeting%202019-01-28/near/157050821" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/weekly.20meeting.202019-01-28.html#157050821">(Jan 28 2019 at 19:26)</a>:</h4>
<p>so, if we were going to discuss chalk integration, can we outline a bit what that would mean?</p>



<a name="157050830"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/weekly%20meeting%202019-01-28/near/157050830" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/weekly.20meeting.202019-01-28.html#157050830">(Jan 28 2019 at 19:26)</a>:</h4>
<p>I am imagining:</p>
<ul>
<li>the idea of a (chalk) query</li>
<li>how the current solver works (i.e., <code>chalk-engine</code>)</li>
</ul>



<a name="157050852"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/weekly%20meeting%202019-01-28/near/157050852" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/weekly.20meeting.202019-01-28.html#157050852">(Jan 28 2019 at 19:26)</a>:</h4>
<ul>
<li>the traits that rustc implements:<br>
    - what are the major callbacks?<br>
    - what stick bits exist?</li>
</ul>



<a name="157050878"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/weekly%20meeting%202019-01-28/near/157050878" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> scalexm <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/weekly.20meeting.202019-01-28.html#157050878">(Jan 28 2019 at 19:27)</a>:</h4>
<p>Yes, then we could mention the <code>program_clauses</code> algorithm, which is basically <em>the</em> major callback</p>



<a name="157050890"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/weekly%20meeting%202019-01-28/near/157050890" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/weekly.20meeting.202019-01-28.html#157050890">(Jan 28 2019 at 19:27)</a>:</h4>
<p>and...maybe looking at the different places <em>in rustc</em> that we use trait queries and how they might interact with Chalk. For examine, a question mark for me is how to make <em>method resolution</em> be more chalk-driven (I want it to be the same as normalization)</p>



<a name="157050900"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/weekly%20meeting%202019-01-28/near/157050900" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/weekly.20meeting.202019-01-28.html#157050900">(Jan 28 2019 at 19:27)</a>:</h4>
<p>ah, perhaps lazy normalization ..? it kind of fits into this category</p>



<a name="157050982"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/weekly%20meeting%202019-01-28/near/157050982" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/weekly.20meeting.202019-01-28.html#157050982">(Jan 28 2019 at 19:28)</a>:</h4>
<p>ok, let me take some notes</p>



<a name="157051170"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/weekly%20meeting%202019-01-28/near/157051170" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/weekly.20meeting.202019-01-28.html#157051170">(Jan 28 2019 at 19:30)</a>:</h4>
<p>OK, I noted down those things. It seems like there is some amount of prep that would make sense. Ideally, I think we would sketch this out as something that can be consumed as "homework", and then perhaps quickly walked over in the meeting itself</p>



<a name="157051193"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/weekly%20meeting%202019-01-28/near/157051193" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/weekly.20meeting.202019-01-28.html#157051193">(Jan 28 2019 at 19:30)</a>:</h4>
<p>but some of these topics are mildly dense</p>



<a name="157051236"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/weekly%20meeting%202019-01-28/near/157051236" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/weekly.20meeting.202019-01-28.html#157051236">(Jan 28 2019 at 19:31)</a>:</h4>
<p>i'm not sure how realistic the 'homework' idea is -- or at least, it's a good idea to prep an outline and so forth, but perhaps not to expect people to really grok it until we are able to talk it out live?</p>



<a name="157051287"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/weekly%20meeting%202019-01-28/near/157051287" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/weekly.20meeting.202019-01-28.html#157051287">(Jan 28 2019 at 19:31)</a>:</h4>
<p>I guess another question is who wants to do that prep :)</p>



<a name="157051336"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/weekly%20meeting%202019-01-28/near/157051336" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> scalexm <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/weekly.20meeting.202019-01-28.html#157051336">(Jan 28 2019 at 19:32)</a>:</h4>
<p>Homework for us or for the people that will listen to us?</p>



<a name="157051342"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/weekly%20meeting%202019-01-28/near/157051342" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/weekly.20meeting.202019-01-28.html#157051342">(Jan 28 2019 at 19:32)</a>:</h4>
<p>both maybe :)</p>



<a name="157051349"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/weekly%20meeting%202019-01-28/near/157051349" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/weekly.20meeting.202019-01-28.html#157051349">(Jan 28 2019 at 19:32)</a>:</h4>
<p>what I meant though is:</p>



<a name="157051365"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/weekly%20meeting%202019-01-28/near/157051365" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/weekly.20meeting.202019-01-28.html#157051365">(Jan 28 2019 at 19:32)</a>:</h4>
<p>I'm trying to get it so that the meetings have a certain amount of "pre-reading" for attendees</p>



<a name="157051372"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/weekly%20meeting%202019-01-28/near/157051372" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> scalexm <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/weekly.20meeting.202019-01-28.html#157051372">(Jan 28 2019 at 19:32)</a>:</h4>
<p>Yes ok</p>



<a name="157051373"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/weekly%20meeting%202019-01-28/near/157051373" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/weekly.20meeting.202019-01-28.html#157051373">(Jan 28 2019 at 19:32)</a>:</h4>
<p>e.g., for the IDE meeting, there is some overview of how RLS works etc</p>



<a name="157051379"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/weekly%20meeting%202019-01-28/near/157051379" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> tmandry <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/weekly.20meeting.202019-01-28.html#157051379">(Jan 28 2019 at 19:32)</a>:</h4>
<p>I'm happy to do it (but currently have more free time than most people do)</p>



<a name="157051410"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/weekly%20meeting%202019-01-28/near/157051410" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> tmandry <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/weekly.20meeting.202019-01-28.html#157051410">(Jan 28 2019 at 19:33)</a>:</h4>
<p>that said, I think it would make the meetings much more productive if we don't have to catch everyone up on basics</p>



<a name="157051412"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/weekly%20meeting%202019-01-28/near/157051412" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/weekly.20meeting.202019-01-28.html#157051412">(Jan 28 2019 at 19:33)</a>:</h4>
<p><span class="user-mention" data-user-id="116883">@tmandry</span> you mean you're happy to try and prep the pre-reading material?</p>



<a name="157051416"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/weekly%20meeting%202019-01-28/near/157051416" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/weekly.20meeting.202019-01-28.html#157051416">(Jan 28 2019 at 19:33)</a>:</h4>
<p>one thing I could imagine:</p>



<a name="157051428"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/weekly%20meeting%202019-01-28/near/157051428" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/weekly.20meeting.202019-01-28.html#157051428">(Jan 28 2019 at 19:34)</a>:</h4>
<p>maybe we create a paper doc and kind of create an outline, and then jointly fill in some details, pointers and things</p>



<a name="157051443"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/weekly%20meeting%202019-01-28/near/157051443" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> tmandry <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/weekly.20meeting.202019-01-28.html#157051443">(Jan 28 2019 at 19:34)</a>:</h4>
<p>I meant <em>read</em> the pre-reading material, but to the extent that I can help prepare it, maybe :)</p>



<a name="157051475"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/weekly%20meeting%202019-01-28/near/157051475" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/weekly.20meeting.202019-01-28.html#157051475">(Jan 28 2019 at 19:34)</a>:</h4>
<p>haha ok :) perfect</p>



<a name="157051488"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/weekly%20meeting%202019-01-28/near/157051488" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/weekly.20meeting.202019-01-28.html#157051488">(Jan 28 2019 at 19:34)</a>:</h4>
<p>tbh part of the reason I want to create the pre-material</p>



<a name="157051489"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/weekly%20meeting%202019-01-28/near/157051489" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/weekly.20meeting.202019-01-28.html#157051489">(Jan 28 2019 at 19:34)</a>:</h4>
<p>is more so that the <em>presenters</em> are organized :P</p>



<a name="157051491"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/weekly%20meeting%202019-01-28/near/157051491" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/weekly.20meeting.202019-01-28.html#157051491">(Jan 28 2019 at 19:34)</a>:</h4>
<p>though I'd love for people to read it</p>



<a name="157051495"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/weekly%20meeting%202019-01-28/near/157051495" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/weekly.20meeting.202019-01-28.html#157051495">(Jan 28 2019 at 19:34)</a>:</h4>
<p>I just know how it goes in practice most of the time...</p>



<a name="157051503"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/weekly%20meeting%202019-01-28/near/157051503" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/weekly.20meeting.202019-01-28.html#157051503">(Jan 28 2019 at 19:34)</a>:</h4>
<p>but even having skimmed an outline often gives you a "feeling", even though we'll wind up going over it</p>



<a name="157051522"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/weekly%20meeting%202019-01-28/near/157051522" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> tmandry <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/weekly.20meeting.202019-01-28.html#157051522">(Jan 28 2019 at 19:35)</a>:</h4>
<p>makes sense</p>



<a name="157051534"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/weekly%20meeting%202019-01-28/near/157051534" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/weekly.20meeting.202019-01-28.html#157051534">(Jan 28 2019 at 19:35)</a>:</h4>
<p>well, anyway, i'm happy to do some of the prep work, <span class="user-mention" data-user-id="131694">@scalexm</span> not sure how much time you have, I could try to send you the paper doc for additions/edits?</p>



<a name="157051641"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/weekly%20meeting%202019-01-28/near/157051641" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/weekly.20meeting.202019-01-28.html#157051641">(Jan 28 2019 at 19:36)</a>:</h4>
<p>(Oh, meta question: I see we're approaching 30 minutes on this meeting, I'm wondering if we want to change the duration to 30 min or maybe 45 instead of an hour? I'm trying to get away from the default of "1 hr" and try to keep things shorter in general.)</p>



<a name="157051646"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/weekly%20meeting%202019-01-28/near/157051646" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/weekly.20meeting.202019-01-28.html#157051646">(Jan 28 2019 at 19:36)</a>:</h4>
<p>/me reclaims their calendar, one minute at a time</p>



<a name="157051655"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/weekly%20meeting%202019-01-28/near/157051655" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> tmandry <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/weekly.20meeting.202019-01-28.html#157051655">(Jan 28 2019 at 19:37)</a>:</h4>
<p>(side note: I'm going through <a href="https://www.amazon.com/Types-Programming-Languages-MIT-Press/dp/0262162091" target="_blank" title="https://www.amazon.com/Types-Programming-Languages-MIT-Press/dp/0262162091">TPL</a> right now and didn't realize how much of the background for chalk was available all in one place)</p>



<a name="157051696"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/weekly%20meeting%202019-01-28/near/157051696" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> scalexm <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/weekly.20meeting.202019-01-28.html#157051696">(Jan 28 2019 at 19:37)</a>:</h4>
<p><span class="user-mention" data-user-id="116009">@nikomatsakis</span> if you have time to start writing a document, I should be able to amend it as needed yes</p>



<a name="157051701"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/weekly%20meeting%202019-01-28/near/157051701" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/weekly.20meeting.202019-01-28.html#157051701">(Jan 28 2019 at 19:37)</a>:</h4>
<p>(also, <span class="user-mention" data-user-id="131694">@scalexm</span> and I had an interesting discussion about implied bounds, and we were debating about a "tweaked" formulation that also sugested some answers to some of our terminology questions from yesterday. )</p>



<a name="157051708"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/weekly%20meeting%202019-01-28/near/157051708" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> scalexm <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/weekly.20meeting.202019-01-28.html#157051708">(Jan 28 2019 at 19:37)</a>:</h4>
<p>Or I could do that in the plane :p</p>



<a name="157051759"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/weekly%20meeting%202019-01-28/near/157051759" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/weekly.20meeting.202019-01-28.html#157051759">(Jan 28 2019 at 19:38)</a>:</h4>
<p>ok, I'm going to try and create 2 outlines, one for the Lowering Rules and one for the Implementation Question sides. This may be ambitious, but it seems helpful regardless.</p>



<a name="157051762"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/weekly%20meeting%202019-01-28/near/157051762" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/weekly.20meeting.202019-01-28.html#157051762">(Jan 28 2019 at 19:38)</a>:</h4>
<p>I'll also see what the scheduling looks like :)</p>



<a name="157051777"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/weekly%20meeting%202019-01-28/near/157051777" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/weekly.20meeting.202019-01-28.html#157051777">(Jan 28 2019 at 19:38)</a>:</h4>
<p>I've added the <code>dyn trait</code> stuff to the breakout list, in case we wind up doing that</p>



<a name="157051922"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/weekly%20meeting%202019-01-28/near/157051922" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/weekly.20meeting.202019-01-28.html#157051922">(Jan 28 2019 at 19:40)</a>:</h4>
<p>thanks all for the feedback! <span aria-label="tada" class="emoji emoji-1f389" role="img" title="tada">:tada:</span></p>



<a name="157053113"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/weekly%20meeting%202019-01-28/near/157053113" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Alexander Regueiro <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/weekly.20meeting.202019-01-28.html#157053113">(Jan 28 2019 at 20:00)</a>:</h4>
<p><span class="user-mention" data-user-id="116009">@nikomatsakis</span> +1 to the meeting about upcasting (and multi-trait objects?)</p>



<a name="157053142"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/weekly%20meeting%202019-01-28/near/157053142" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Alexander Regueiro <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/weekly.20meeting.202019-01-28.html#157053142">(Jan 28 2019 at 20:00)</a>:</h4>
<p><span class="user-mention" data-user-id="116009">@nikomatsakis</span> would also be good to talk about lazy normalisation and some of the things it can solve. I think we need to really prioritise fixing type alias bounds now.</p>



<hr><p>Last updated: Aug 07 2021 at 22:04 UTC</p>
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